RESEARCH OF PROBLEMS ON REALIZING DIRECT ALGORITHM OF WAVELET TRANSFORM

Direct algorithm of wavelet transform (WT) is the numerical algorithm obtained from the integral formula of WT by directly digitization. Some problems on realizing the algorithm are studied. Some conclusions on the direct algorithm of discrete wavelet transform (DWT), such as discrete convolution operation formula of wavelet coefficients and wavelet components, sampling principle and technology to wavelets, deciding method for scale range of wavelets, measures to solve edge effect problem, etc, are obtained. The realization of direct algorithm of continuous wavelet transform (CWT) is also studied. The computing cost of direct algorithm and Mallat algorithm of DWT are still studied, and the computing formulae are obtained. These works are beneficial to deeply understand WT and Mallat algorithm. Examples in the end show that direct algorithm can also be applied widely.     

STUDY ON INJECTION AND IGNITION CONTROL OF GASOLINE ENGINE BASED ON BP NEURAL NETWORK

According to advantages of neural network and characteristics of operating procedures ofengine, a new strategy is rapresented on the control of fuel injection and ignition timing of gasolineengine based on improved BP network algorithm. The optimum ignition advance angle and fuelinjection pulse band of engine under different speed and load are tested for the samples trainingnetwork, focusing on the study of the design method and procedure of BP neural network in engine     

MECHANISM ON DISTRIBUTION OF PILOT FUEL SPRAY AND COMPRESSING IGNITION IN PREMIXED NATURAL GAS ENGINE IGNITED BY PILOT DIESEL

Numerical simulations of pilot fuel spray and compressing ignition for pre-mixed natural gas ignited by pilot diesel are described. By means of these modeling, the dual fuel and diesel fuel ignition mechanism of some phenomena investigated on an optional engine by technology of high-speed CCD is analyzed. It is demonstrated that the longer delay of ignition in dual fuel engine is not mainly caused by change of the mixture thermodynamics parameters. The analysis results illustrate that the ignition of pre-mixed natural gas ignited by pilot diesel taking place in dual fuel engine is a process of homogenous charge compression ignition.     

RESEARCH ON THE ADAPTIVE CONTROL OF DRILLING PROCESS

ＲＥＳＥＡＲＣＨＯＮＴＨＥＡＤＡＰＴＩＶＥＣＯＮＴＲＯＬＯＦＤＲＩＬＬＩＮＧＰＲＯＣＥＳＳＺｈａｎｇＦｅｉｈｕ；ＹｕａｎＺｈｅｊｕｎＹａｏＹｉｎｇｘｕｅ；ＣｈｅｎＳｈｕｏｄｏｎｇ（ＨａｒｂｉｎＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ）Ａｂｓｔｒａｃ...     

STRATEGIES FOR SOLVING KEY PROBLEMS IN RESEARCH AND DEVELOPMENT OF AUTOMOTIVE CONTINUOUSLY VARIABLE TRANSMISSION

ＳＴＲＡＴＥＧＩＥＳＦＯＲＳＯＬＶＩＮＧＫＥＹＰＲＯＢＬＥＭＳＩＮＲＥＳＥＡＲＣＨＡＮＤＤＥＶＥＬＯＰＭＥＮＴＯＦＡＵＴＯＭＯＴＩＶＥＣＯＮＴＩＮＵＯＵＳＬＹＶＡＲＩＡＢＬＥＴＲＡＮＳＭＩＳＳＩＯＮ①ＨｕａｎｇＸｉａｎｇｄｏｎｇＹａｎｙｕＬｉｎＢｉｎ...     

RESEARCH OF MOVEMENT NAVIGATION BASED ON ASSEMBLY CONSTRAINT RECOGNITION

0 INTRODUCTIONThe traditional assembly design stresses the final result of assembly modeling, but pays little attention to the process of assembly simulation. Nonetheless, the procedure of assembly is a cardinal element that determines the quality of assembly modeling. These drawbacks hinder the advancement of the speed and quality of assembly design. Moreover, in the traditional mode of product development, designers make prototypes to evaluate the function and appearances of products. P…     

RESEARCH ON SEARCH AND RECOGNI-TION FOR CONSTRAINT BASED ON COMPREHENSION OF GRAPH

A promising approach on the search for geometric constraint of directional graph in off-line parametric design has been put forward . The method for representation of the directional graph is given firstly , then the constraint model for every geometry element is put forward . By the search of geometric constraint, it sets up the topology constraint relation on the different element objects , which are not related in geometry data base, and achieves the identify for the directional graph . The algorithm of recognizing geometric constraint is described in detail, in the meantime, the application example in off-line parametric design on dimension-driven is given .     

ANALYSIS AND RESEARCH OF COMPUTER-AIDED MODEL OF HIP JOINT BASED ON REVERSE ENGINEERING

Former research work about the modeling of hip joint focus on the upper segment of femoral, and assumes the acetabulum cup is sphere concave, and the acetabulum prostheses is semisphere. A method of acquiring the point data on the surface of the hipbone using the reverse engineering technology is presented. After analyzing the acetabulum surface fitting error, a rotation ellipsoid CAD model is applied to fit the acetabulum surface, and then optimization technique is used to find the geometric parameters of the model. The fitting error between the sphere and rotation ellipsoid is compared and gets the result that the fitting error of rotation ellipsoid is smaller than sphere, and the rotation ellipsoid can describe the shape of the acetabulum better.     

RESEARCH ON THE PERFORMANCE OF NEW TYPE OF PROPORTIONAL PESSURE AND FLOW CONTROL VALVE

A new closed loop flow controlling principle through correcting the valve's opening area while load pressure is changing is carried out. Further more a principle using only one proportional valve to compound control pressure and flow is suggested. By using very simple proportional throttle valve in structure, the functions that five kinds of proportional valves or any two of them combined possess can be complimented. After analyzing, comparing, and testing the dynamic and static characteristics of valve with different controlling principles and main valve structure styles, the optimized structure styles and control methods are achieved.     

RESEARCH ON COMBINATION AND PLANNING OF PROCESSING UNITS UNDER CIMS CONDITION

ＲＥＳＥＡＲＣＨＯＮＣＯＭＢＩＮＡＴＩＯＮＡＮＤＰＬＡＮＮＩＮＧＯＦＰＲＯＣＥＳＳＩＮＧＵＮＩＴＳＵＮＤＥＲＣＩＭＳＣＯＮＤＩＴＩＯＮＲＥＳＥＡＲＣＨＯＮＣＯＭＢＩＮＡＴＩＯＮＡＮＤＰＬＡＮＮＩＮＧＯＦＰＲＯＣＥＳＳＩＮＧＵＮＩＴＳＵＮＤＥＲＣＩＭＳ...     

IMPROVEMENTS ON THE CONFIGURATION AND OPTIMUM PARAMETERS OF HIGH一SPEED THRUST BEARINGS

ＩＭＰＲＯＶＥＭＥＮＴＳＯＮＴＨＥＣＯＮＦＩＧＵＲＡＴＩＯＮＡＮＤＯＰＴＩＭＵＭＰＡＲＡＭＥＴＥＲＳＯＦＨＩＧＨ一ＳＰＥＥＤＴＨＲＵＳＴＢＥＡＲＩＮＧＳＩＭＰＲＯＶＥＭＥＮＴＳＯＮＴＨＥＣＯＮＦＩＧＵＲＡＴＩＯＮＡＮＤＯＰＴＩＭＵＭＰＡＲＡＭＥＴＥＲ...     

OPTIMUM CONTROL OF VIBRATION AND STRUCTURE－BORNE NOISE FOR MACHINERY ON FLEXIBLE FOUNDATION

ＯＰＴＩＭＵＭＣＯＮＴＲＯＬＯＦＶＩＢＲＡＴＩＯＮＡＮＤＳＴＲＵＣＴＵＲＥ－ＢＯＲＮＥＮＯＩＳＥＦＯＲＭＡＣＨＩＮＥＲＹＯＮＦＬＥＸＩＢＬＥＦＯＵＮ－ＤＡＴＩＯＮＯＰＴＩＭＵＭＣＯＮＴＲＯＬＯＦＶＩＢＲＡＴＩＯＮＡＮＤＳＴＲＵＣＴＵＲＥ－ＢＯＲＮＥＮ...     

RESEARCH ON EXPERT SYSTEM OF FAULT DETECTION AND DIAGNOSING FOR PNEUMATIC SYSTEM OF AUTOMATIC PRODUCTION LINE

Fault detection and diagnosis for pneumatic system of automatic production line are studied. An expert system using fuzzy-neural network and pneumatic circuit fault diagnosis instrument are designed. The mathematical model of various pneumatic faults and experimental device are built. In the end, some experiments are done, which shows that the expert system using fuzzy-neural network can diagnose fast and truly fault of pneumatic circuit.     

RESEARCH ON DESIGN METHOD OF A MULTIPLE DISC WET BRAKE IN LUBRICATED ENVIRONMENT

The rmomechnical phenomena occurring between friction pairs greatly change the distributions oflining pressure and friction surface temperature of a multiple disc wet brake. It has become one of the maincauses of brake failure. In order to understand these thermomechanical phenomena, several design and mate-rial factors tha have great influence on thermomechanical phenomena, such as heat transfer coefficient, fric-tion factor, sliding velocity initial lining pressure and so on, are analyzed. An isothermal design method isproposed for designing a multiple disc wet brake.     

RESEARCH ON MODEL AND METHOD OF NETWORK-BASED COOPERATIVE COMMERCE CHAIN IN AUTOMOBOLE INDUSTRY

Based on the analysis on the development of the cooperative commerce in automobileindustry,the systematic model of the cooperative commerce chain in automobile industry is illustrated,the flow of agent-based NCCC (network-based cooperative commerce chain) system is described, andthe method and NCCC system in automobile industry are developed, and so the correctness and thefeasibility of the theory and the method are confirmed.     

DIRECT AND ADAPTIVE SLICING ON CAD MODEL OF IDEAL FUNCTIONAL MATERIAL COMPONENTS （IFMC）

A brand new direct and adaptive slicing approach is proposed, which can apparently improve the part accuracy and reduce the building time. At least two stages are included in this operation: getting the crossing contour of the cutting plane with the solid part and determining the layer thickness. Apart from usual SPI algorithm, slicing of the solid model has its special requirements. Enabling the contour line segments of the cross-section as long as possible is one of them, which is for improving manufacturing efficiency and is reached by adaptively adjusting the step direction and the step size at every crossing point to obtain optimized secant height. The layer thickness determination can be divided into two phases: the geometry-based thickness estimation and the material-based thickness verifying. During the former phase, the geometry tolerance is divided into two parts: a variety of curves are approximated by a circular arc, which introduces the first part, and the deviation error between the contour     

CONSTRUCTION OF G~2 CONTINUOUS CURVES ON SURFACE WITH PLANAR CUBIC BZIER CURVES

The problem of constructing curve on parametric surface (or surface that can be parameterized) such that it interpolates a sequence of points with prescribed tangent direction and curvature vector (or geodesic curvature) at every point and the issue of curve blending on this kind of surface are researched. The mapping and tangent mapping from the surface to its parametric plane are introduced and thus several conclusions with differential geometry are deduced. Based on those conclusions, the problem of interpolating (or blending) curve on a parametric surface is converted to a similar one on its parametric plane. The final solution curve of either interpolation or blending issue is explicit and can still be expressed by parametric form. And so, unlike existing methods, the presented method needs not to use any surface/ surface intersection algorithms, usually a troublesome process, for displaying such interpolation curve. Experiment results show the presented methods are feasible and applicable to CAD/CA     

RESEARCH ON THE DYNAMIC PROPERTY OF PIEZOELECTRIC MICRO DISPLACEMENT ACTUATOR FOR BORING ERROR COMPENSATION

The dynamic property of piezoelectric micro displacement actuator (PMDA) is analyzed, especially the mechanical characteristic, lag phase property and hysteresis phenomenon. The influence factors of static and dynamic mechanical characteristics and the lag phase property are analyzed systematically. Three main influence factors of lag phase property are discovered. With comparison to mechanical Coulomb friction, a generalized model of nonlinear hysteresis of PMDA is advanced, based on the essential analysis of nonlinear phenomenon. Finally the application of PMDA in error compensation control system of boring is introduced. A good compensation result is achieved.     

RESEARCH ON MODELING AND CHARACTERISTICS OF THE SPINDLE DYNAMIC COUPLING ABSORBERING SYSTEM OF A SUPER－PRECISION SURFACE GRINDING MACHINE

The bearing is described by constrain matrix, and the spindle system of a NC surface grinding machine is simplified as elastic-coupling beam, then modal synthesis method is used to establish the dynamic model of beam. Moreover, the response of the end of rotor is analyzed, and the natural frequency, principle mode and other dynamic characteristics of the coupling system are studied, the law of bearing stiffness to coupling frequency and amplitude of rotor is also found. Finally, according to the actual condition, a dynamic absorber is designed. The simulation and experimental results show that the amplitude of spindle can be declined effectively when the dynamic absorber is attached.